Module 19 - senses

Question 1

sound waves

Answer 1

• mechanical waves - need a medium to travel through
• oscillation between compression and rarefaction

Question 2

amplitude in sound waves

Answer 2

• intensity of energy
• determines the loudness of the sound

Question 3

wavelength in sound waves

Answer 3

• length in space of each cycle of the wave
• determines the pitch of sound

Question 4

frequency in sound waves

Answer 4

• how fast the wave cycles
• high frequency = short wavelength = high pitched sounds
• low frequency = long wavelength = low pitched sounds
• humans can hear frequencies from about 20Hz to about 20 kHz (about 56 ft to about 2/3 of an inch)
• gradually lose sensitivity to high frequencies with age

Question 5

how do sound waves travel?

Answer 5

• dont travel in a straight line
• emanate from the sound source in all directions

Question 6

how do we hear sound in terms of waves?

Answer 6

• most sounds are complex
• made up of multiple component sine waves with different frequencies, amplitudes, and phases (starting positions in the cycle)

Question 7

what type of frequencies are more easily blocked by obstructions

Answer 7

• high frequencies
• that is why consonants can be more easily muffled than vowels

Question 8

pinna

Answer 8

• outside of the ear
• acts as a cup to catch sound

Question 9

external auditory canal

Answer 9

• goes from pinna to inner ear

Question 10

tympanic membrane

Answer 10

• ear drum
• vibrated by sound waves

Question 11

ossicles

Answer 11

• tiny bones in the inner ear
• amplify vibrations from the tympanic membrane to the cochlea

Question 12

cochlea

Answer 12

• contains fluid that sound travels through
• different frequencies stimulate different parts of the cochlea more than others
• has receptors (hair cells) that transduce the energy into neural impluses

Question 13

auditory nerve

Answer 13

• transmits neural impulses from the cochlea to the brain

Question 14

ways we perceive sound location

Answer 14

• inter-aural differences
• inter-aural timing
• high/low and front/back info based on the way the sound hits the pinna
• visual and context clues

Question 15

olfaction

Answer 15

• sense of smell
• detecting odorants
• different receptors in the nose to detect different chemicals
• most odors are a pattern of stimulation of multiple different receptors

Question 16

odorants

Answer 16

• small, airborne molecules that have odors (stimulate olfactory receptors

Question 17

parts of olfactory system

Answer 17

• nasal cavity
• olfactory nerves (with receptors on the ends)
• olfactory bulb
• olfactory tract/cortex

Question 18

what makes olfactory sensory information different from other sensory information

Answer 18

• it isn’t routed through the thalamus before reaching the cerebral cortex
• instead goes directly to the primary olfactory cortex

Question 19

taste buds

Answer 19

• cluster of taste receptors
• mostly on tongue, but also elsewhere in the mouth
• different types of taste receptors respond to different types of molecules

Question 20

4 basic tastes

Answer 20

1. salty
   - NaCl and other salts
2. sour
   - acids
3. bitter
   - various molecules, including many poisons
4. sweet
   - simple carbohydrates

Question 21

2 additional tastes

Answer 21

• umami/savory - monosodium glutamate (MSG), a salt present in some protein-rich foods
• fat - fatty acids

Question 22

senses that contribute to flavor

Answer 22

• gustatory (taste) and olfactory (smell)
• tactile information from the mouth
• ex: chocolate and cinnamon flavors are mostly produced by smell

Question 23

insula

Answer 23

• located deep in the cerebral cortex at the junction between the frontal, parietal, and temporal lobes
• location of primary gustatory processing
• sometimes considered a “fifth lobe”